The primary objective of the studies outlined in this proposal is to isolate and characterize epidermal proteins that are associated with growth and aging. The studies are extensions of our preliminary findings that suggest age-associated differences in soluble proteins. One such protein in rat epidermis studied earlier undergo changes between neonatal and adult life span. Our specific aims are to focus mainly on the studies of other soluble fractions which we have identified earlier and in addition, extend our studies to nuclear proteins, histones and non-histones. Particular emphasis will be placed on proteins which binds to DNA and those proteins which show growth and age-associated differences either in their composition or in their synthesis. We will use Wistar rats and obtain the epidermal tissue either by stretch technique or by soaking the skin in anmonium chloride. The proteins will be isolated by homogenization and fractionation techniques. In isolation and characterization of proteins, several recent methods such as chromatofocusing and western-blot techniques will be employed for better results. Further characterization will be based upon biochemical and immunological criteria. Specific antisera will be produced to study intracellular localization and methods and will be developed to quantitate the distribution of specific protein in epidermal tissue of various age groups. The interactions of proteins with DNA will be studied to correlate the functional and biochemical changes during aging. These studies on non-keratin epidermal proteins as a function of age will be important in understanding the differentiation of young and old epidermis and provide knowledge to the biological gerontology of the skin at the molecular level.